According to the World Health Organization (WHO), the Ebola virus, formerly known as Ebola hemorrhagic fever, "causes an acute, serious illness which is often fatal if untreated." The virus is thought to originally come from fruit bats, and can be transmitted between humans through broken skin or mucous membranes, according to the WHO, via blood, secretions or other bodily fluids, and through surfaces and materials as well. Ebola is not transmitted through the air, according to the U.S. Centers for Disease Control (CDC).

The virus is also transmitted through breast milk and semen, and people remain infectious as long as it is in their bodily fluids. For men, the virus can remain in their semen for up to seven weeks after recovering from Ebola.

Symptoms of Ebola include fever of 101.5°F and above, fatigue, muscles aches, headache, sore throat, vomiting, diarrhea, unexplained bruising and sometimes internal and external bleeding, according to the CDC.

Although the virus is highly contagious, precautions can be taken to prevent transmission between people, including using gloves and protective equipment when treating an infected patient. Precautions should also be used when handling a dead body of someone who has died from Ebola.